He racked up a staggering 113 league goals in 122 league appearances for the Ligue 1 champions.
United boss Jose Mourinho has previously worked with the striker at Inter Milan and the pair are known to be good friends.
In his autobiography I am Zlatan, he wrote: Jose Mourinho is a big star. He’d been my manager at Inter. He’s nice.
“The first time he met my partner Helena, he whispered to her: ‘Helena, you have only one mission: feed Zlatan, let him sleep, keep him happy.’ That guy says whatever he wants.